Shower or bath: Which uses more water?

“Take showers instead of baths to save energy,” is an oft-repeated adage of water and energy conservation advocates. But the Department of Energy’s water-heater-sizing pages now list the average shower as consuming 12 gallons and the average bath only 9 gallons of hot water. 

The DOE is also saying that homeowners are using from 15 to 30 percent of their total energy budget just to heat water—up from an earlier 14 to 25 percent estimate. So is soaking instead of scrubbing the way to go?

A spokeswoman for the EPA (which provided the figures to the DOE) says the new figures were based on a study it commissioned in 2000 by independent water-engineering-and-management firm Aquacraft. Ten homes in Seattle were fitted with data loggers on the main water meters a separate meter was placed on the feed line to the water heater and the results measured over two separate two-week periods.

“The nine gallons was actually the actual average draw of water into a bathtub, but you’re talking about an event that can involve more than one draw of hot water,” says Aquacraft President Bill DeOreo. “So that’s not an accurate measure of total average use.”

Consumer Reports’ own experts believe the previous 20 gallons of hot water per bath that the EPA was using (which was in turn based on a studies done by the Gas Appliance Manufacturers Association) to be still a better benchmark.

They also stress that the best way to save hot water is to take showers rather than baths, limit the time of showers, use a low-flow showerhead, and turn off any supplemental showerheads in each shower stall.

Many utilities and municipalities are following this advice. The Portland, Oregon Water Bureau has given away over 4,500 1.5- gallon-per-minute showerheads and 4,000 five-minute “Shower Timer” hourglasses to its customers.

“The hourglasses aren’t as functional as the low-flow showerheads and aerators we give away; they’re more of a behavioral tool,” says Sarah Statner of the Portland Water Bureau. “But we get a lot of positive feedback and hear they inspire more conversations about conservation than any showerhead every will.”

Also backing the move for water economy is the popular eco-blogger Crunchy Domestic Goddess, who has issued her own Five-Minute Shower Challenge that’s drawn numerous responses.—Gian Trotta

Essential information: Find out about the wide variety of high- and low-flow spraying options available Showerheads special. Our GreenerChoices.org Web site offers "50 Ways to Save Water." And see our October issue for a special comparing the performance of tankless, or on-demand, and conventional storage-tank heaters.

Comments

[Kalani Aylett]

Turn the water off while soaping down. Trying to wash with soap while the shower water is spilling over your body doesn't make sense. You'll get a lot cleaner and waste less water.

[Richard]

I don't believe the DOE figures!

[Samuel Levine]

Nine gallons of water... are you kidding me. I bet the EPA folks use 20 + gallons per bath. Only a child would be happy with 9 gallons of water. Give me a break EPA.

[Brad Vanasse]

My average-sized tub is about 20" x 50" inside and so takes about 4 gals per inch of water depth. So nine gallons seems a little light to me, too.

[R/T]

The way I read that is they are measuring only how much HOT water is being used.so if you assumed a 60/40 mix of hot and cold you would draw a total of 15 gallons of water (only 9 of hot)and a 50/50 mix would give you a total of 18 gallons in the tub

[vsorensen]

Why not just measure our own usage?

Run the shower for as long as you typically do, with the plug in. When the time is up, is the tub as full as you would have it for a bath?

[talent agent's daughter]

doesn't it all depend on how long you take a shower? sometimes i can start thinking about stuff while i'm in the shower and i totally lose track of time... i all of a sudden realize i'm staring at the wall with water beating on my back for the last 25 mins! probably not the best use of water.. but may be good for stress!

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[Robert F. English]

This is a highly useful article. As some other readers have commented, I shower BUT shut the water off each time I soap up/shampoo in between rinses. I run the shower for the total of about a minute.
I don't believe in restricted-flow shower heads; they have insufficient pressure. Why not just encourage people to run the water for shorter periods?
Thanks

[Russell]

You also have to take into account the hardness of the water.

Where I am, the water is soft and it takes forever to get the soap off, if you can get it off. Not being able to the soap off makes you feel sweaty all the time. Whereas in other areas with hard water, I can take a shower in only a few minutes and feel clean all day long.

The only purpose of soft water I can see is to make soap suds, not to actually clean anything better.

[mj]

you have to compare apples with apples. I bathe instead of shower because I shave my legs in the tub. My baths run about 20 minutes. If I showered for 20 minutes I'd use a lot more water than one tub full. For me showers are only good for a quick clean up after a workout.

[john]

I'LL USE AS MUCH WATER AS I PLEASE THANK YOU! GET A LIFE PEOPLE.....

[Jon Voskuil]

I don't know what time of year the study was done, but at my house the water-heating cost for a shower or bath varies a lot from season to season, for three reasons.

First, the temperature of the water coming into the house is now about 65 (in August). In the winter it's much colder, maybe 45. Heating the water an extra 20 degrees in the winter uses more energy.

Second, because the cold water is colder in the winter, I have to mix more hot water with it at the faucet to get the same shower temperature. So I use more heated water in the winter for the same shower.

Third, I like a warmer shower in the winter and a cooler shower in the summer, which means I use still more heated water for a winter shower.

[perry degener]

What other cities are giving away these low usage shower heads? Are any cities in Maryland?

[swimmer]

you HAVE to be kidding! Enjoy life! Live it, love it and quit worrying about the water. The water we have NEVER goes away. it goes into the ground, evaporates, etc. It NEVER EVER goes away!!!!!!! wake up.

[Aaron Thompson]

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[jen]

Water "NEVER EVER goes away!!!!!!"? You are the one who needs to "wake up."

If water is constantly being cleaned and recycled through the earth’s water cycle, why do we need to conserve it? The answer is that people use up our planet’s fresh water faster than it can naturally be replenished. Water is not a finite resource, but potable water, the water we use to drink, irrigate crops and bathe in is. To provide enough clean fresh water for people, water is cleaned at drinking water treatment plants before it is used. And after water is used, it is cleaned again at wastewater treatment plants or by a septic system before being put back into the environment. This uses a great deal of energy.

The goals of water conservation efforts include:

* Sustainability - To ensure availability for future generations, the withdrawal of fresh water from an ecosystem should not exceed its natural replacement rate.
* Energy conservation - Water pumping, delivery, and wastewater treatment facilities consume a significant amount of energy.
* Habitat conservation - Minimizing human water use helps to preserve fresh water habitats for local wildlife and migrating waterfowl, as well as reducing the need to build new dams and other water diversion infrastructure.

Excessive use of water has the following adverse effects on our society, economy, and environment:

· More dams must be built, destroying wilderness areas and reducing streamflow.
· The water infrastructure requires increased maintenance for pipes, sewers, and treatment facilities.
· Agricultural uses can contribute to erosion, salinity and increased desertification.
· Water bodies such as rivers, wetlands, and bays are degraded from the high levels of water extracted and from the polluted runoff that feeds into them.
· Conserving water now can keep down the costs of developing new sources of water. Conservation stretches our water supply, helping sustain us during the long time-frame it takes to develop new sources of supply.

[Jena]

wtf?!?! what matrials do you need to tell what uses more water; a bath or a shower?!

[anonyomous]

@samual-i am a kid! i use as much as 15 gallons!>=(

[jeremiah carswell]

im trying to find the materials to which uses more water a shower or a bath